1. Field of the Invention
The invention relates to a roller, more particularly to a roller having a self-contained induction generator device.
2. Description of the Related Art
The improvement of this invention is directed to a conventional roller mounted rotatably on a roller shaft of a scooter. The roller is generally provided with a light emitting unit and a dry battery for supplying electricity to the light emitting unit. Since the dry battery needs to be replaced frequently, a roller with a self-contained generator device has been proposed, so as to eliminate the need to replace the dry battery in the conventional roller.
Referring to FIGS. 1 and 2, a conventional roller 1, which is adapted to be mounted rotatably on a horizontal roller shaft 16 of a scooter (not shown), is shown to include a roller housing 10, a light emitting unit in the form of two bulbs 14, and an induction generator device 13.
As illustrated, the roller housing 10 includes two housing halves 11 which are interconnected removably and which define an accommodation chamber 102 therebetween. The housing halves 11 are mounted rotatably on the shaft 16 by means of two bearing units 15. Each of the housing halves 11 has a shaft-extension hole 101 so that it is adapted to be sleeved rotatably on the shaft 16 in such a manner that the shaft 16 extends through the shaft-extension holes 101 in the housing halves 11. The bulbs 14 are mounted within the housing 10. One of the housing halves 11 is formed with a pair of diametrically disposed light passage holes 111 via which illumination from the bulbs 14 are visible from an exterior of the housing 10.
The induction generator device 13 is disposed within the accommodation chamber 102 of the housing 10, and includes a permanent magnet 135 that is sleeved securely on the shaft 16 and that has two opposite vertical side surfaces 131, and a winding unit consisting of a sheave 130 and a coil unit 132 that is wound on the sheave 130 and that is in electrical connection with the bulbs 14. The sheave 130 is sleeved rotatably on the magnet 131, and is further fixed to the housing 10. Two ring-shaped vertical electrically and magnetically conducting plates 133 are mounted fixedly in the housing 10 and are in electrical and coaxial connection with the coil unit 132. Each of the conducting plates 133 has a plurality of elongated axially extending sheets 134 which are angularly spaced apart from each other and which extend into an annular space defined between the magnet 131 and the sheave 130. Under this condition, when the roller 1 rotates about the shaft 16, electricity is generated on the coil unit 132 so as to intermittently light up the bulbs 14, thereby emitting a flashing light from the roller 1 via the light passage holes 111.
Because the sheets 134 are disposed around the shaft 16, magnetic lines of force passing through the sheets 134 are relatively few, thereby resulting in a limited induced electromotive force. In addition, the permanent magnet 135 is isotropic, and made from barium-based iron oxide powder. The number of magnetic lines of force generated therefrom is relatively small, thereby adversely affecting generation of electricity for illumination of the bulbs 14.
The object of the present invention is to provide a roller having a self-contained induction generator device of a unique structure which is capable of serving as a more effective electrical power source for lighting a light emitting unit disposed on the roller.
Accordingly, a roller of the present invention is adapted to be disposed rotatably on a horizontal roller shaft of a scooter. The roller includes a roller housing, a light-permeable rim element, a light emitting unit, and an induction generator device. The roller housing includes two housing halves, which are interconnected removably and which define an accommodation chamber therebetween. Each of the housing halves has a shaft hole adapted to be sleeved rotatably on the shaft in such a manner that the shaft extends through the shaft holes. The light-permeable rim element is sleeved fixedly on the housing. The light emitting unit is disposed within the rim element. The induction generator device is disposed within the accommodation chamber of the housing, and includes a mounting tube, a permanent magnet, a winding unit, and two ring-shaped vertical electrically and magnetically conducting plates. The mounting tube is adapted to be sleeved fixedly on the shaft. The permanent magnet is shaped as a vertical ring plate that is sleeved non-rotatably on the mounting tube and that has two opposite vertical side surfaces. The winding unit includes a sheave and a coil unit that is wound on the sheave and that is in electrical connection with the light emitting unit. The sheave is sleeved rotatably on the magnet, and is fixed to the housing. The conducting plates are mounted fixedly in the housing, and are in electrical and coaxial connection with the coil unit. Each of the conducting plates has an inner ring, an outer ring, and a plurality of elongated radially extending sheets which are angularly spaced apart from each other and which have radial inner ends that are formed integrally with the inner ring, and radial outer ends that are formed integrally with the outer ring. When the roller rotates about the shaft, electricity is generated on the coil unit so as to intermittently light up the light emitting unit, thereby emitting a flashing light from the roller via the rim element.